Key Considerations

"What good quality, metal-bodied, small/compact/trim rotary tool/cut-out tool/router/spindle with collet size between 6.35 and 3mm is available w/ a diameter of <70mm, and a power rating of >100 Watts (500 or more is highly desirable and arguably a reasonable minimum[12]), and a weight of <2Kg?".

Smaller diameters are better (move the endmill closer to the axis of movement)

More power is better w/in reason

low runout (captured in the phrase "good quality" above) is the most important characteristic.

A suitable collet size is a key consideration, and the want of it will require either an adapter (which complicates things and may increase runout) or a custom collet (which adds to the cost).

Machine Types

Rotary Tool --- the prototypical hobbyist tool. Dremel is the most-recognized brand name and widely available. A small hand-held unit intended for small, delicate work. Collets are typically aluminum sleeves available in a variety of diameters shaped to fit the machine's shaft end and held in place by a nut, 0.125" is typical..

Cut-out Tool --- A commercial tool intended to cut drywall, as a class was inaugurated by the RotoZip Spiral Saw. Collets are similar to rotary tools, but typically only 0.125" and 0.25" diameters are available.

Router --- The first powered woodworking tool, it allowed a woodworker to use a collection of small bits to create profiles which used to require either individual hand planes, or a combination plane such as a Stanley 45 which was viewed by most as finicky and difficult to set up. Routers are now available in a number of different sizes, w/ various terms being used to describe a over-lapping ranges of devices. Collets are usually specific to a machine and the stock collets are typically only available in 0.25" or larger sizes. Custom collets of various types are available, some of which afford conveniences like to industry-standards such as ER.

Spindle --- the generic term for any device for spinning an Endmill mounted on a machine, it's also used to signify a unit which is intended for being so mounted. Previously, only expensive, high-quality commercial units were available, but spindles suited for hobby-level equipment have become available of late. Usually these use industry standard collets such as ER.

The sort of collet and sizes in which they are available is a significant concern in selection and can dramatically affect the final price of a unit. It may be best to consider the sorts of cutting which one wishes to do, select an Endmill and match the spindle choice to that.

One additional concern is how different power ratings are measured. Commercial/Industrial spindles are rated for their sustained output (root mean square, RMS power). Consumer devices such as rotary and cut-out tools and routers are typically rated at their (theoretical) peak horsepower.[13] For example the Makita RT070x-series has (as the name implies) a 700 Watt power rating, but is described as being 1.25 HP, which ~=933 Watts. The table below should use actual power ratings rather than peak so as to allow comparisons --- please update (with references) if any peak ratings are found.

Compatibility

Please note that the hole spacing for the inner pair of holes on the Shapeoko 3 is the same as that as on the ShapeOko 2, or for the MakerSlide used for the ShapeOko 1, so mounts are compatible between the machine designs if no other geometry interferes.

Power Considerations

"2.2kw is about 3 HP. 1 HP is 745W, 745*3 = 2235W (which isn't far from 2.2 * 1000). W/V=A, therefore 2235W/110V = 20.31 A, and thats assuming no losses in your transformer/inverter, voltage drop in your household wiring or other equipment running on the same circuit. Most 110V outlets are 15A though there are some rated for 20A. The reason you don't see any inverters that turn 110V power into 220/3ph power above a certain HP/kW rating is that there simply isn't enough amperage on the circuit to drive them." [14]

100 to 999 Watts

A note on the low-end rotary tools --- pretty much anything w/ at least 100 Watts of power (or 0.8 Amps @ 110VAC) will be workable --- there are probably too many re-badged variants (Sears Craftsman effect) to list them all, unless there is some extra-ordinary reason to warrant a listing (the tools currently listed are shown due to their widespread availability while still being a good value). Depending on one's patience and expectations and materials, one could go much lower (there's a 9-volt DC tool which would probably be quite kid-safe / friendly) if one took light enough cuts.

This tool has two different/distinct diameters, so will not mount plumb in the stock mounts --- one can make up the narrower diameter using a suitable size of zip tie around the tool aligned with the lower mount.

The DWP611 - better choice than the DW660, I think it's a tad bit quieter, but seems to be more robust, with less plastic and more metal. If using a speed control system, it is possible to modify the 611 to bypass the built-in variable speed control and to place the optical sensor within the router housing.[44]

Variable speed, the actual no load speeds of one unit were measured as:

The Makita RT0700C/0701C(X) - seems to be similar in kind to the DWP611. Same sort of aluminium housing and speed control, but without the two LEDs underneath. The 0701 is slightly newer and is intended for the North American market. The 0700 is still available as a 220V model for Europe and other localities which use that voltage.[61] Another difference for the two models seems to be the screw layout for the base(s), w/ the newer 0701 having a standard Porter Cable layout.

Harbor Freight (HF) Trim Router --- details on using the stock mount w/ strapping (thread now includes .svg file for a mount and dust shoe). Alternately, one can use the stock mount by using longer bolts 70--75mm.

The Chinese Foredom knockoff - This is a pretty good little spindle. For the most part you can only get to 3/16" shank, which isn't really an advantage over 1/8" because the bits are so hard to find, but what it does get you is "off-site" power. It uses a flexible wand connected to an AC motor. The motor turns between 15-20k RPM. I used one of these for about 6 months before it died. You can see it in my phone dock video (see list of videos below). The foredom knockoff is to-date my favorite choice *IF* I could get it with a 1/4" collett. It's good enough that I've contemplating buying a non-knockoff foredom handpiece just to see if it's any better, but at $355 I'm not sure that's ever going to happen. Because of what EJ was talking about (mounting the majority of the weight) off the machine, gives some great advantages. One that wasn't mentioned is the fact that the tool itself is closer to the z-axis, creating less of a lever arm.

DC Spindle

Generic

180 Watts

15,000 -- 20,000 r.p.m.

48v

This is ninja quiet!

The 180w DC spindle (48v) - And IMO does a nice job with simple engraving features, but is SERIOUSLY lacking in the power category. Don't plan to cut much (or anything) with this. I don't do PCB engraving, but imagine this thing would be great.

DC Spindle

Generic

1/4" ER-11

300 Watts (6.25 amps)

3,000 -- 12,000 r.p.m.

48v

~1.73 pounds

The 300w DC spindle (48v) - This is the second quietest spindle on the list. It's still lacking in power compared to even the knockoff dremel, but can manage to cut through most woods & plastics if treated nicely (1/32" (0.79375 mm) depth pass). It also has a 1/4" ER-11 collett option, but IMO is worthless because of the lack of power. Blog post about it here.

The Colt - This thing is a MONSTER! It's loud as hell, and weighs more than any of the others (excepting the heaver Dewalt ), and is pretty big, but it can really tear some stuff up. Cat saw it run first hand on one of my prototype machines when he was in Chicago last month and could attest to it's sheer power. I used a 1/4" 2 flute Onsrud bit and tore through a piece of maple at 1/4" depth pass without the Colt even flinching. Discussion in the forums here. European model is GKF-600[76]. Notable features include:

even weight distribution

compact

long, high-quality cord

Variable speed, the actual no load speeds of one unit were measured as:

The next one on my list is the 800w water cooled VFD. At $379, it's pricey, but this one runs off 110v, so the need for a 220v drop isn't required. The 220v versions are about the same price, but most people don't have 220v available and would have to pay an electrician to get it installed.

List of Videos

Collets and Adapters

A collet is a holding device that forms a collar around the endmill to be held and exerts clamping force on the tool when tightened, usually by means of a tapered outer collar. Adapters are sleeves which fit w/in collets allowing them to hold smaller size bits.

Collets are either industry-standard, specific to a given design, or a custom aftermarket part. The aftermarket collets are made to higher standards, usually of better steel, and will reduce runout. They also avoid the need to use adapters.

Spindle Control

Single-speed spindles can also be controlled using a router speed control as noted in Less Power on the Dewalt DW660 page. One concern with using speed control on the DW660 (and similar units) is that it is cooled by a fan on the motor shaft, which works fine at high speed and low to moderate torque. When you reduce the speed and increase the torque (by using closed-loop speed control), the cooling becomes insufficient.[93]